The Hangar 9 Spitfire Mk IXc ARF is an excellent model. Built following the instructions it will be an excellent aircraft you’ll enjoy flying for many years. To add a little personal touch and enhance some of the scale detail I added a few modifications to the kit. They are not intended to be exact scale modifications, merely a few tweaks to help it standout for other Spitfire ARFs on the flight-line.

Cockpit

The ARF was designed to accommodate a pilot bust figure using a decal dash included in the kit. My goal was to change the stock arrangement to full cockpit with a more realistic looking instrument panel. A few minutes using Google and I had plethora of images of Spitfire instrument panels & cockpits. Using an inkjet printer I scaled one of the panels to fit the 1/5.5 scale H9 Spitfire. The instrument panel consists of three layers;

Card stock cut to correct shape with holes punched in locations of instruments.

Clear plastic cut in the outline of instrument panel.

Face of instrument printed on glossy paper.

The holes in panel were made using hole punches, available in various sizes from card making or scrapbook supply stores (or your wife’s Stampin’Up! supplies).

I glued the three layers together using Weldbond taking care not to have glue in location of instruments.

You can add as much detail as you want to the panel using ‘googled’ photos for reference. Making switches from pins and small bits of balsa or ply.

The rest of the cockpit was built using 1/16 balsa in a TLAR (That Looks About Right) fashion that fit the cockpit.

The interior was painted “cockpit green” using acrylic toll paints.

Guns & Cannons

To create the illusion of firing guns & cannons orange ultrabright LEDs were used. The outboard guns used a 3mm LED glued(thin ZAP) in a ½” section of aluminum tube. The top section of the molded cannon was cut off replaced by a 5mm LED glued(thin ZAP) in a ½” section of brass tube. Solder a red & black wire to the LEDs (approx.. 20” long) use heat-shrink tubing to prevent the LED from shorting, red wire to the positive side of LED. A 100-150ohm resistor soldered in-line with the positive lead of LED.

Mount the cannon following the directions of kit, route the wires though wing us servo connector on the ends to make disconnecting possible.

Drill 1/8” hole in the center of red square of wing leading edge. Route wire to aileron servo bay, then to wing route. Glue the tube with LED flush with leading edge of wing, using

There are a few companies that make R/C accessories to flash lights/LEDs to simulate cannon fire. Using a 555 timer I constructed two circuits using the schematic below. The 20mm cannons in a Spitfire fired at a rate of 600rpm (10Hz) & the .303 guns at 1200rpm (20Hz). Using a circuit flashing at these rates the LED appeared to be on all the time. To give the illusion of firing I slowed the rate to 5Hz & 7Hz respectively. The table show the values of resistors & capacitor to use in circuit to create the correct frequency.

RPM

Frequency

R1

R2

C1

1200

20Hz

3Kohm

15Kohm

2.2uF

600

10Hz

1Kohm

15Kohm

4.7uF

420

7Hz

4.7Kohm

100Kohm

1uF

300

5Hz

6.8Kohm

27Kohm

4.7uF

Retracts

The retracts used are servoless electric retracts from HobbyKing to fit a 50cc Spitfire. To retro fit this gear, the legs needed to be shortened approximately 2”. This was accomplished by drilling the center of the gear leg an additional 2” deep using a 15/64” drill bit. After drilling the leg was cut 1 78″ shorter using a hacksaw, taking care to keep the cut square, then file the end to remove any burrs or sharp edges. Using a drill press the gear leg was then drilled and tapped using the same spacing to accomidate the grub screws. Once this mod is complete the gear can be installed following the kit/gear directions.

Tail Wheel

To give the appearance of a “scale-ish” tail wheel a little 1/8” balsa was used. Following the directions of the kit the wheel collar was located 2” from the end on the tail-wheel wire. Short strips of 1/8” balsa ¾” wide was then glued around the wire, this was then sanded to shape (images from google search as a guideline). Use 1/64” ply & balsa to create the ‘fork’. The balsa & ply sections of tail-wheel were then covered using a head shrink film (gray or chrome)